Calibration Procedure for Sieves and Screens

Calibration of Sieves Below or equal to 30# :

Check the cleanliness of sieve before start the calibration.

Affix “Under Calibration” label

Take the plain paper and mark with pen one linear square inch in the paper with the help of calibrated standard measuring scale.

Keep the marked paper below the sieve and count the apertures with the help of magnifying glass and count the number of holes in linear square inch in both the directions (Horizontal and Vertical directions).

Take minimum ten location counts in each sieve.

Calibration of sieve above 30# to 100# by using Densimeter :

Keep densimeter on the sieve in such a way that the letters are facing us and other side is touching the sieve.

Move the densimeter so that any one vertical line of densimeter is matching with the vertical line of the sieve.

Grids will start forming on the densimeter. Peak of grid form like the peak   of the mountain.

The line of this peak where it matches the sieve / number mentioned on  the densimeter is the actual sieve number of the sieve.

Take minimum ten location counts in each sieve.

TOLERANCE LIMIT :

TOLERANCE LIMIT :

Sr No.	Sieve Size	Number of Apertures per Linear Inch
1	10 #	9-11
2	12#	11-13
3	14#	13-15
4	16#	15-17
5	20#	19-21
6	24#	23-25
7	30#	28-32
8	40#	38-42
9	60#	57-63
10	80#	77-83
11	100#	97-103

1. if any new sieve are received that needs to be calibrated before issue  to the production.

2. Damaged sifter sieve should not calibrate and use.

      

Calibration of Screen using ‘GO’ and ‘NO-GO’ Gauges :

Screen Used in Milling

Insert ‘GO’ gauge in a screen, it should passes though the screen.

Insert ‘NO-GO’ gauge in the same screen, it should not passes  through the screen.

Note :

1.Calibrate all the sieve and screens once in six months.

2. If any discrepancy observed immediately inform to the executive  production or department head for the necessary action.

3. All the new sieves and screens needs to be calibrated before issued to the    production

4. Damaged sieve and screens should not calibrate and used.